Computer attacks originating in China tried to break into the email accounts of US government officials, military personnel and Chinese political activists, Google says.

But the country's foreign ministry has rejected the claims, saying "blaming these misdeeds on China is unacceptable".

Ministry spokesman Hong Lei said: "Hacking is an international problem and China is also a victim.

"The claims of so-called support for hacking are completely unfounded and have ulterior motives."

Shandong province was also the origin of a cyber attack on Google’s computer systems in 2009 - an assault that soured the company's relations with the Chinese government, and prompted Google to move its Chinese-language site to Hong Kong.

More recently, a company in Shandong was linked to a cyber attack on several of the world’s biggest oil companies.

According to internet security company Symantec, China is the source of nearly 30% of the world’s malicious emails.

Though it is impossible to prove conclusively that the attacks are linked to the Chinese government, experts have long suspected official involvement in hacking activities originating in the country.

Google has had an uneasy relationship with the Chinese regime

A series of incidents - including the Google attacks of 2009, and the discovery of the Ghostnet cyber espionage network in the same year - have targeted foreign governments, Beijing-based diplomats, Chinese political activists and journalists.

The Tibetan government-in-exile has also been a repeated victim.

A recent investigation revealed murky connections between hackers and the Chinese Government.

A conference organised by hackers in a Beijing hotel was sponsored by an internet security firm with connections to the Chinese military, and was attended by Chinese police officers.

"Phishing" attacks work by sending an email containing a link or attachment that, when opened, installs "malware" on the target’s computer, allowing the hacker to steal information.

To succeed, the victim must believe that the email is authentic. Google says the subject line of one of the emails sent in the recent attack was "Fw: Draft US-China Joint Statement".

The latest attack comes following an announcement from American officials that deliberate infiltration of vital US information networks may be considered an "act of war".

Earlier this week, a Pentagon spokesman told the Wall Street Journal that the US would consider "all appropriate options" in response to foreign cyber attacks.

"If you shut down our power grid, maybe we will put a missile down one of your smokestacks," he said.

Britain is also a major target for foreign hackers. Cybercrime and internet espionage are now estimated to cost the UK £27bn a year.